1. Field of the Invention
The present invention is directed to a device of supplying a concentrated CO.sub.2 gas in a carbonate spring bath system which is capable of cooling, at an improved cooling rate, a CO.sub.2 gas adsorption tower for supplying the concentrated CO.sub.2 gas.
2. Description of the Prior Art
When a bath water including a CO.sub.2 gas is used in a bath, it is known that blood circulation in human a body is improved by taking the bath and fatigue is relieved. Japanese Patent Early Publication [KOKAI] No. 3-131259 describes a carbonate spring bath system, as illustrated below. Such bath system includes a combustor for supplying a combustion gas carrying the CO.sub.2 gas, a CO.sub.2 gas adsorption tower and a vacuum pump for desorbing a concentrated CO.sub.2 gas from the adsorption tower and sending it to a bathtub. Stream included in the combustion gas is removed by a dehumidifier prior to sending the combustion gas to the CO.sub.2 adsorption tower. However, as a desorption amount of the CO.sub.2 gas is controlled by the vacuum pump, it is difficult to stably supply the concentrated CO.sub.2 gas to the bathtub. On the other hand, the Japanese Patent Early Publication [KOKAI] NO. 3-131259 also describes another carbonate spring bath system, as illustrated below. That is, such bath system includes the combustor, a pair of steam adsorption towers for adsorbing the steam from the combustion gas and a separation film for separating the CO.sub.2 gas from the combustion gas. The steam adsorption towers are arranged between the combustor and the separation film. As the steam adsorption towers is used alternately to adsorb the steam, the bath system is effectively operated. However, because the CO.sub.2 gas is not stored in the separation film, it is difficult to increase a concentration of the CO.sub.2 gas. Moreover, as a plurality of air pumps and the adsorption tower are used in the bath system, the bath system becomes an expensive system having a complex structure.